Methods of forming a variable watt density layered heater

Abstract

Methods of forming a layered heater are provided that comprise at least one resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a length, a thickness, and a spacing, wherein the thickness varies along the length of the trace of the resistive circuit pattern for a variable watt density. The methods include achieving the variable thickness by varying a dispensing rate of a conductive ink used to form the resistive circuit pattern, varying the feed rate of a target surface relative to the dispensing of the ink, and overwriting a volume of conductive ink on top of a previously formed trace of the resistive circuit pattern.

1. A method of forming a trace of a resistive circuit pattern of a layered heater, the trace defining a length, a width, and a spacing, the method comprising the steps of:
 (a) dispensing a conductive ink through an orifice of a single writing tip at a rate onto a surface; and 
 (b) selectively varying the dispensing rate of the conductive ink through the orifice of the writing tip to form a variable thickness trace of the resistive circuit pattern. 
 
     
     
       2. A method of forming a trace of a resistive circuit pattern of a layered heater, the method comprising the steps of:
 (a) dispensing a conductive ink through an orifice of a single writing tip at a rate onto a surface; and 
 (b) selectively varying a feed speed of the substrate relative to the dispensing of conductive ink through the orifice of the writing tip to form a variable thickness trace of the resistive circuit pattern. 
 
     
     
       3. A method of forming a trace of a resistive circuit pattern of a layered heater, the method comprising the steps of:
 (a) applying a volume of conductive ink onto a surface with a single dispensing element to form the trace; and 
 (b) subsequently applying an additional volume of conductive ink onto the trace with the single dispensing element after the volume of step (a) has been applied along the entire trace, 
 wherein a variable thickness trace of the resistive circuit pattern is produced. 
 
     
     
       4. The method according to  claim 3 , wherein the volumes of conductive ink are applied by a layered process selected from the group consisting of thick film, thin film, thermal spraying, and sol-gel. 
     
     
       5. The method according to  claim 3 , wherein the volumes of conductive ink are applied using precision pen writing equipment. 
     
     
       6. The method according to  claim 3 , wherein the volumes of conductive ink are applied using a silk screening process. 
     
     
       7. A method of forming a trace of a resistive circuit pattern of a layered heater, the trace defining a length, a width, and a spacing, the method comprising forming the trace with a variable thickness. 
     
     
       8. The method according to  claim 7 , wherein the variable thickness is formed along the length of the trace of the resistive circuit pattern. 
     
     
       9. The method according to  claim 7 , wherein the variable thickness is formed across the width of the trace of the resistive circuit pattern. 
     
     
       10. The method according to  claim 7 , wherein the trace of the resistive circuit pattern is formed by a process selected from the group consisting of thick film, thin film, thermal spraying, and sol-gel. 
     
     
       11. The method according to  claim 3 , wherein the volumes of conductive ink are applied using a thick film process. 
     
     
       12. The method according to  claim 3 , wherein the volumes of conductive ink are applied using a thin film process. 
     
     
       13. The method according to  claim 3 , wherein the volumes of conductive ink are applied using a thermal spray process. 
     
     
       14. The method according to  claim 3 , wherein the volumes of conductive ink are applied using a sol-gel process. 
     
     
       15. The method according to  claim 7 , wherein the volumes of conductive ink are applied using a thick film process. 
     
     
       16. The method according to  claim 7 , wherein the volumes of conductive ink are applied using a thin film process. 
     
     
       17. The method according to  claim 7 , wherein the volumes of conductive ink are applied using a thermal spray process. 
     
     
       18. The method according to  claim 7 , wherein the volumes of conductive ink are applied using a sol-gel process. 
     
     
       19. The method according to  claim 7 , wherein the trace is formed with a variable thickness continuously. 
     
     
       20. The method according to  claim 7 , wherein the trace is formed with a variable thickness non-continuously.